EA Pure Pond Gel Balls are biodegradable balls, crammed full of live bacteria that are slowly released when they are needed most. With over 8,000,000,000 bacteria per litre of Pure Pond Balls, your pond will shine even more than normal, especially if you add them regularly into your Kaldnes moving bed, or into any other type of filter you may have. When you introduce the Pure Pond balls into the biological chamber of your Nexus, they become one with moving bed, agitating alongside the K1 media, just waiting to smooth out any peaks and troughs of the Ammonia/Nitrite cycle, to give you even healthier, crystal clear water. Works equally well in any filter type made (both static and fluidized), as well as in skimmers and filterfall units. Pure Pond are time released, and so will last for several months in your system. No need for regular treatments!